1. Field of the Invention
The present invention relates to a dry cutting apparatus for pavement when constructing sewerage or underground gas pipes, for example, and to a road processing apparatus such as a grooving apparatus for making a plurality of grooves in order to prevent vehicles on a road from slipping and, more particularly, to a dry cutting and grooving apparatus for pavement structured so as to quickly collect and remove chips and cutting powder in order to improve cutting efficiency.
2. Description of Related Art
Conventionally, there have been known a road cutting apparatus for linearly cutting a surface of a pavement and a grooving apparatus for making a multiplicity of grooves on a curve or a steep slope of a general road, and pavement of an airport.
These road cutting apparatus and the grooving apparatus are provided with a diamond blade as a member for cutting and grooving, and the basic structure thereof is to rotate the diamond blade at a high speed and to cut the pavement by moving the blade into the pavement.
Among these road cutting apparatuses and the grooving apparatus, a so-called wet-type apparatuses which supplies water for removing chips and cutting powder as well as for cooling the diamond blade during operation, has been mainly used. However, since the chips and cutting powder are mixed into the supplied water and flow onto pavement, the pavement becomes soaked with the polluted water. Thus, it has been necessary to collect and remove the water after operation.
Further, when cutting and grooving pavement with a diamond blade, it is considered more important to remove chips and cutting powder from the surface of the blade than to cool down the blade.
Namely, since chips and cutting powder accumulating during the operation with the passage of time enter into an area between the processed surface and the blade, it is unavoidable to generate heat in the blade due to friction between these interposing substances and the blade. Therefore, the chips and cutting powder should be removed. When chips and cutting powder are not positively removed, the blade is bent due to heating of the blade so that cutting efficiency is widely lowered and the cut surface is deteriorated due to deformation, thereby inviting inferior processing.
On the other hand, in place of this wet-type processing, a dry-type processing in which no water is supplied has also been known. A road cutting apparatus and a grooving apparatus used for the dry process are provided with an air suction mechanism for collecting dust in a housing which covers around the blade.
FIG. 23 is a schematic view which shows a main portion of a structure for sucking chips and cutting powder from the housing in a conventional apparatus.
An illustrated example shows an apparatus for cutting pavement, wherein a housing 52 surrounding a periphery of a blade 51 which includes diamond abrasive grains and is connected to a drive mechanism disposed in a body of a cutting apparatus is integrally mounted to the body end, and a duct 53 for sucking is disposed in front of the housing 52. The duct 53 is connected to a vacuum pump disposed in the body end.
The blade 51 rotates clockwise in the drawing which is the same direction as the rotating direction of a wheel when the body is running, and linearly cuts a paved portion on the road by this rotation.
When a suction port of the duct 53 is open to the front portion of the housing 52 in a manner mentioned above, it is possible to collect chips and cutting powder generated during cutting by sucking up them.
However, although a part of fine particles within the housing 52 is sucked into the duct 53, the fine particles are likely to touch both surfaces of the blade 51 and tend to be forced by swirling flow in the same direction as the rotating direction of the blade caused by the blade 51 itself. Particularly, when the blade 51 rotates at a high speed, a swirling force to the same direction as the rotating direction of the blade 51 is applied to the fine particles including the chips and the cutting powder.
Accordingly, the fine particles within the housing 52 do not simply float, but they are given fluidity by a high-speed rotation of the blade 51, so that a suction force of the duct 53 is reduced. Particularly, in a portion corresponding to a suction port of the duct 53, since the fine particles swirl downward, the fine particles go to the direction opposite to the sucking direction of the duct 53, so that sucking efficiency of the duct 53 is widely lowered.
As mentioned above, despite the suction duct 53 provided in the housing 52, the fine particles such as chips and cutting powder are forcibly fluidized by influence of the high-speed rotation of the blade 51, and thus the fine particles are scattered from the housing 52. Further, since the blade 51 is heated up by such fine particles entering between the blade 51 and a processed surface of the pavement, which leads to low efficiency and deterioration of the processed surface.
On the contrary, in the grooving apparatus for simultaneously cutting a plurality of grooves on pavement for preventing slippage, for example, since a multiplicity of blades are disposed on the same axis to form the grooves, more fine particles are generated in comparison with pavement cutting. Furthermore, since the generated fine particles are fluidized in a portion between a pair of blades, not a single blade, disposed at an interval, a fluidizing force due to a forcible swirling flow mentioned above are larger, which lowers efficiency of collecting the fine particles by the duct.
A diamond wheel having diamond abrasive grains on the peripheral surface as a segment is used for the blade 51. In this case, a cutting surface of the wheel is gradually worn as an operation time becomes longer. Accordingly, the blade 51 has to be frequently replaced and is often replaced at the construction site.
However, since the blade 51 is rotated at a high speed, and also resistance of the pavement when cutting is large, the rigidity of a fixing structure to an apparatus body for cutting or grooving pavement must be high. Thus, the structure of a member for supporting the blade 51 is complex, and it requires a lot of time to remove the main rotation shaft for the blade 51 from the apparatus body and to reassemble the main rotation shaft. For example, when the blade 51 is a single blade as in the illustrated example, an operation time interrupted by replacement is not much; however, in the case of the grooving apparatus in which a plurality of blades for simultaneously cutting a multiplicity of grooves for preventing slippage are coaxially disposed, a replacing operation requires a long time due to the large number of the blades.
As mentioned above, in cutting and grooving pavement in accordance with the conventional dry-type process, although there are some advantages that contaminated water is not generated and a cleaning operation is not required, it cannot be avoided that the environment is deteriorated due to scattered fine particles outside and cutting efficiency is lowered due to heat generation and deformation of the blade caused by the fine particles entering into the processed surface. Further, since the replacing operation of the blade is complex and requires a lot of time, there is a problem that operation efficiency is further lowered.